This invention relates to payload or stores carriers for attachment to a vehicle. The carrier of this invention is particularly suited for usage with an aircraft as a carrier of one or more air-launched missiles, although it may be used with other military payloads including, but not limited to, air-launched or air-ejected missiles to be used in air-to-air or surface-to-surface combat operations, prepackaged missiles in cannisters for deployment over land or sea areas, deployable or dispersible electronic countermeasures equipment, sensor packages, miniaturized pilotless aircraft, rescue gear, replenishment supplies, and other logistics support equipment. It will be understood therefore that an air-launched missile (ALM) is disclosed herein as a particular payload item for illustrative purposes and that this invention may be used with all other payloads and carrier vehicles not explicitly mentioned herein.
The advent of ALM's has fostered the need for available aircraft capable of delivering one or more ALM's. Military aircraft, of course, offer a nucleus of available ALM carrier vehicles; however, it would be desirable to increase the number of available ALM carrier aircraft beyond military aircraft. To this end, non-military or commercial aircraft have been considered as possible ALM carriers, provided that these aircraft could be temporarily transformed into configurations suitable for military missions. (This temporary transformation is referred to hereinafter as "reversible conversion.") According to this reversible conversion concept, an aircraft designed and operated for commercial air transportation (passenger, freight, or combination) could be used as an ALM carrier without irreversible modification of its structure, avionics, or other essential elements. Likewise, a military aircraft originally not designed as an ALM carrier (e.g. patrol, surveillance, transport or tanker aircraft) could be used for this purpose, again without requiring irreversible modifications of its structure, avionics, or other essential elements. According to further aspects of this concept, the aircraft, following the temporary military use, can be essentially recovered in its original configuration without significant refurbishing, except for the possible damage suffered in the course of military operations. Following minimal refurbishment, it will have the same functional performance characteristics as prior to the military employment period.
Reversible conversion heretofore has not been practical because the converted aircraft configuration has been unsatisfactory from the standpoint of flight performance obtained or structural modification required. Some converted configurations typically create excessive drag, or impose additional stresses or fatigue on the aircraft above original design allowables. Other converted configurations require excessive structural modification. These converted configurations may be characterized as internal carry and external carry.
In the internal carry configuration, it is in general required to reinforce the floor in which the payload will be carried and to modify the cargo doors or other exit openings through which it can be loaded on the ground and discharged in flight. Missiles preferably should be launched with their longitudinal axis along the direction of flight. This through the currently existing openings in commercial passenger aircraft is just about impossible. Launching in other than this preferred orientation causes serious stress and flight dynamic problems in the inflight ejection operation. Reinforcement of the loading floor and structural modifications of the launch openings are in general expensive, not only in terms of direct cost but also owing to the duration of modifications which take the airplane out of commercial service with the concomitant loss of revenue. The additional reinforcement results in permanent payload penalty over extended peacetime periods before the actual military use (possibly as long as the operational life of the aircraft), the user is thus forced to suffer the corresponding revenue loss. This in turn calls for undesirable reimbursement via direct payments or privileges through regulatory decisions.
In the external carry configuration, payload packages such as missiles or cannisters are attached to the outside of the aircraft. In this instance, of course, drag and aero-elastic stability problems become important considerations. In general, structural modifications are required to provide the hard point or mounting posts upon which the load can be attached. Drag can be avoided by providing appropriate fairings; but with current designs (usually referred to as conformal carriages), such fairings must also be attached to the structural strong points of the aircraft. Once again, structural modifications to the extent that they cause payload penalty and availability loss are undesirable as explained above. Another form of external carry makes use of a rotary rack, such as that used in military aircraft, mounted in an aerodynamically shaped pod to be carried on a single strong-point built in one of the wings of certain commercial aircraft. (The original design purpose of the strong-point was to carry a spare engine.) The military payload that can be carried under such conditions, however, is of limited weight.